genode/base-hw/src/core/kernel_support.cc
Stefan Kalkowski 8393ac6895 base-hw: implement vm_session for TrustZone
* Introduces Schedule_context
* Use fast-interrupts or normal interrupts
* Add mode-transition between secure/non-secure world
* Limit system resources for Genode apps due to non-secure world

This commit implements the newly introduced Vm session interface to be used
on top of TrustZone capable Armv7 CPUs. Therefore a new Schedule_context is
introduced in the kernel. Threads and Vms are both Schedule_contexts used
by the scheduler. In contrast to a thread a vm uses a different assembler
mode switch to the non-secure, virtual world, as well as another exception
is used, when the non-secure world is left. For both worlds to co-exist
the interrupt-controller needs to be configured, so that the secure (Genode)
world uses fast-interrupts only, and the non-secure world only legacy
interrupts.
The only TrustZone capable platform the base-hw kernel works on top of
is the CoreTile Express 9x4 for the Versatile Express motherboard. For a
virtual machine working properly on top some platform resources must be
reserved. Therefore there exist two flavours of this platform now, one with
the 'trustzone' spec-variable enabled, and one without. If 'trustzone' is
specified most platform resources (DDR-RAM, and most IRQs) are reserved
for the Vm and not available to the secure Genode world.
2012-10-29 10:08:30 +01:00

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/*
* \brief Kernel function implementations specific for Cortex A9 CPUs
* \author Stefan Kalkowski
* \date 2012-10-11
*/
/*
* Copyright (C) 2012 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#include <kernel_support.h>
Cpu::User_context::User_context()
{
/* Execute in usermode with IRQ's enabled and FIQ's and
* asynchronous aborts disabled */
cpsr = Cpsr::M::bits(Cpsr::M::USER) | Cpsr::F::bits(1) |
Cpsr::I::bits(0) | Cpsr::A::bits(1);
}